Enzyme Donor Stabilization Buffer


Catalog #: B2010001 (50 mL)

A specially designed buffer that stabilizes the beta-galactosidase fragment known as enzyme donor (Alpha fragment). The buffer can extend the shelf life of the enzyme donor to up to 12 months at 2° – 8°C. Without this buffer, the enzyme donor is highly instable and loses activity at an extremely high rate.

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Enzyme Donor Stabilization Buffer (Beta-galactosidase).

Catalog # B2010001
Size 50 mL
Storage 2° – 8°C.
Buffer Buffered solution at pH 7.4 with proprietary stabilizers and preservatives specially formulated for the enzyme donor.
Application Alpha complementation kit, cloned enzyme donor immunoassays, ELISA.
Keywords Beta-galactosidase Alpha Peptide, Beta-galactosidase Enzyme Donor, Beta-galactosidase Omega Domain, Enzyme Acceptor, Alpha Complementation, LacZ.
Related products Beta-galactosidase Enzyme Donor (Alpha Peptide), Stabilization Buffer for Enzyme Acceptor, Beta-galactosidase Enzyme Acceptor (Omega Domain), Beta-galactosidase Enzyme Acceptor Stabilization Buffer, Beta-galactosidase Chromogenic Substrate.


About Beta-galactosidase Alpha Complementation

Beta-galactosidase Alpha-Complementation is a biochemical phenomenon first documented by Agnes Ullmann, while working in the lab of François Jacob and Jacques Monod. By means of molecular cloning, the native E. coli β-galactosidase enzyme can be split in two inactive fragments of different sizes. The smaller fragment, known as the alpha-peptide or enzyme donor, is about 100 amino residues in length and is inactive on its own (incapable of hydrolyzing a β-galactosidase substrate). The larger fragment, known as the omega fragment or enzyme acceptor, is about 900 amino residues in length and is also inactive on its own. Upon mixing the enzyme donor with the enzyme acceptor, the β-galactosidase enzyme is reconstituted and is now capable of hydrolyzing colorimetric substrates such as ONPG.

Both enzyme donor and enzyme acceptor can be cloned and expressed in special E. coli strains to yield highly pure, zero-background enzyme fragments (i.e. an enzyme donor and enzyme acceptor without measurable catalytic activities, when assayed individually). Interestingly, it was discovered that various analytes can be conjugated to the enzyme donor moiety and the enzyme donor-enzyme acceptor association modulated by an analyte-binding molecule (such as an antibody). As a result, an alpha-complementation-based assay can be developed.

Download Alpha Complementation Product Line Brochure.


  • Kras, E. (2019). Beta-galactosidase: properties, structure and functions. New York: Nova Science Publishers.
  • Arndt, T. (2017). Cloned Enzyme Donor Immunoassay. Lexikon Der Medizinischen Laboratoriumsdiagnostik, 1–2.
  • Jeon, S. I., Yang, X., and Andrade, J. D. (2004). Modeling of homogeneous cloned enzyme donor immunoassay. Analytical Biochemistry, 333(1), 136–147.
  • Tachi, T., Kaji, N., Tokeshi, M., and Baba, Y. (2009). Microchip-based Homogeneous Immunoassay Using a Cloned Enzyme Donor. Analytical Sciences, 25(2), 149–151.
  • Khanna, P. L., and Worthy, T. E. (1993). CEDIA: A Recombinant-Based Homogeneous Enzyme Immunoassay.

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Additional information

Weight 32 oz
Dimensions 8 × 6.75 × 5.5 in

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